Dietary loading and aggrecanase-1/TIMP-3 expression in rat mandibular condylar cartilage.
Dietary loading and aggrecanase-1/TIMP-3 expression in rat mandibular condylar cartilage.
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发表时间：
2007
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通讯作者：
Dahai Yu;Petri A. Tiilikainen;A. Raustia;P. Pirttiniemi
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作者：
Dahai Yu;Petri A. Tiilikainen;A. Raustia;P. Pirttiniemi
目的研究断奶后不同时间点不同饮食负荷下幼龄大鼠髁突软骨中聚集酶-1和金属蛋白酶组织抑制剂（TIMP-3）的表达，并确定两者之间的关系。方法将100只sd大鼠随机分为2组，软饲组为对照组（n=50），硬饲组为实验组（n=50）。分别于断奶后6小时、12小时、24小时、48小时和9天（即硬日粮大鼠开始改食后）处死10只软日粮大鼠和10只硬日粮大鼠。制备右侧颞下颌关节（TMJs）进行免疫组化染色。每组10只动物左髁软骨联合Western blot分析。结果免疫组化分析显示，在两组患者的所有时间点，聚集酶-1的强染色主要集中在增殖区和上增生性软骨带的软骨细胞中。硬饮食组在12和24小时的免疫组织学上聚集酶-1的表达明显高于软饮食组。两组各时间点TIMP-3的强染色主要集中在增殖带和上肥厚带软骨细胞。硬饮食组TIMP-3的表达在6小时时显著低于软饮食组。Western blot分析显示，两组患者聚集酶-1、TIMP-3的表达也存在时间相关差异，但两组间差异无统计学意义。结论聚合酶-1和TIMP-3表达的暂时变化反映了这些酶在生理范围内的复杂相互作用和软骨对改变饮食负荷的反应。
AIMS To examine the expression of aggrecanase-1 and a tissue inhibitor of metalloproteinases (TIMP-3) in the condylar cartilage of young rats and to determine their relationship during altered dietary loading at different time points after weaning. METHODS One hundred Sprague-Dawley rats were randomly assigned to 1 of 2 groups: the soft-diet group, which served as the control group (n=50), or the hard-diet group, which served as the experimental group (n=50). Ten soft- and 10 hard-diet rats were killed at 6 hours, 12 hours, 24 hours, 48 hours, and 9 days after weaning (i.e., after initiation of diet change for hard-diet rats). The right-side temporomandibular joints (TMJs) were prepared for immunohistochemical staining. The cartilage from the left-side mandibular condyles of all 10 animals in each group was combined for Western blot analysis. RESULTS Immunohistochemical analysis revealed strong staining for aggrecanase-1 localized mainly in the chondrocytes of proliferative and upper hypertrophic cartilage zones at all time points in both groups. The immunohistological expression of aggrecanase-1 was significantly higher in the hard-diet group at 12 and 24 hours than in the soft-diet group. Strong staining for TIMP-3 was mainly localized in the chondrocytes of proliferative and upper hypertrophic zones at all time points in both groups. The expression of TIMP-3 in the hard-diet group was at a significantly lower level compared to the soft-diet group at 6 hours. Western blot analysis also showed time-related differences in aggrecanase-1 and TIMP-3, but there was no significant difference between the 2 groups. CONCLUSION The temporary change in aggrecanase-1 and TIMP-3 expression reflects the complex interaction of these enzymes in the physiologic range and cartilage response to altered dietary loading.